Environ. Sci. Technol. 1996, 30, 3362-3370
Spatial Distribution in Plankton and Bioaccumulation Features of Polychlorinated Naphthalenes in a Pelagic Food Chain in Southern Part of the Baltic Proper JERZY FALANDYSZ* Department of Environmental Chemistry & Ecotoxicology, University of Gdan ˜ sk, ul. Sobieskiego 18, PL 80-952 Gdan ˜ sk, Poland
CHRISTOFFER RAPPE Institute of Environmental Chemistry, Umea˚ University, S-901 87 Umea˚, Sweden
High-resolution GC/MS with electron impact (EI) and selected ion recording (SIR), after a nondestructive sample extraction and cleanup using semipermeable polyethylene membrane (SPM), and further HPLC fractionation on activated carbon column were applied to determine polychlorinated naphthalenes (PCNs) in a pelagic food web including mixed subsurface plankton, Baltic herring (Clupea harengus), and harbour porpoise (Phocoena phocoena). Nearly all theoretically possible tetra- through heptachlorine substituted naphthalene congeners were identified and quantified in all samples examined. The concentrations, profile, and patterns of PCNs found in spatially different plankton samples indicate the atmosphere as a dominating long-range transportation and deposition route of these pollutants into the southern Baltic proper. Biological matrix-dependent variations found in the compositional pattern of chloronaphthalene congeners indicate selective and structure-dependent metabolism as well as the retention of some PCNs within a pelagic food chain studied.
Introduction Polychlorinated naphthalenes (PCNs) are primairy industrial chemicals, which were introduced to a common practice as dielectric fluids, flame retardants, and fungicides since the beginning of the nineteenth century (1-3). These substances can actually be found in old type and are still in service in some electric equipment (capacitors, transformers, cables, and wires) (4) as well as the impurities in technical chlorobiphenyl (PCBs) formulations (5, 6). The identified sources of PCNs are connected to various * Author to whom correspondence should be addressed; fax: +4858-410357; telephone: +48-58-415271, ext. 272.
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reactions in which chlorine is present, such as chlorine production, and include thermal processes during municipal solid waste incineration (MSWI), copper roasting, and degradation of polychlorinated alkenes (7-13). Altogether, 74 of 75 possible chloronaphthalenes were identified in fly ash and flue gas samples from the MSWI, while some congeners have not be found in technical PCNs formulations such as Halowax mixtures (10, 12). The thermal pattern of PCN congeners found in the fly ash, flue gas, and circulating water samples of the waste incinerator is totally different from that of Halowax 1014 or EquiHalowax (a mixture containing equal amounts of Halowax 1000, 1001, 1013, 1014, 1031, 1051, and 1099) (7, 9-12). Mono- and dichloronaphthalenes were the only PCN congeners found after experimental degradation of polychlorinated alkenes (13). The pine needle samples collected in various distances from the point source of pollution with Halowax 1001 display, like a typical abiotic samples, a pattern of PCNs highly resembling the original mixture (14). Polychlorinated naphthalenes are lipophilic, persistent, and bioaccumulating chemicals, and evidence exists that these substances become widespread pollutants in the environment, that co-occur in different matrices to the bulk quantities of polychlorinated biphenyls (PCBs), organochlorine pesticides, and many other known and unknown organohalogens (15-18). Development in synthesis of all individual PCN congeners (3, 11, 12, 19-21) made possible a congener-specific determination of these compounds in various environmental matrices. Patterns of PCNs or their particular homologue groups become known for the Halowax 1014 and Equi-Halowax mixtures as well as for such abiotic samples as flue gas, fly ash, circulating water of MSWI and a technical PCB mixture of Kanechlor KC-400 (6, 8-12). Composition of PCN congeners has been described also for the Yusho rice oil and adipose fat of the victim of Yusho poisoning (6). On the other hand, data on occurrence of PCNs in the general population are very scare. These contaminants, namely, three isomers of hexachloronaphalene and one isomer of pentachloronaphthalene, were detcted and quantified in adipose fat of the general population in Canada (22), while they remained undetected in adipose fat of the Japanese (6). The data on concentrations, compositional pattern, and bioaccumulation features of PCNs in wildlife are also generally lacking, and only recently have congener-specific analyses have been made for white-tailed sea eagles (Haliaeetus albicilla), sediment, and biota from the Gdan ˜ sk Basin, Baltic Sea (23, 24). The occurrence of many congeners of PCNs in fishes, crabs, and mollusc from the Gulf of Gdan ˜ sk, Baltic Sea, implies that seafood can be a very important source of nearly all tetra- to hepta-CNs for human beings. Chloronaphthalenes are toxic to exposed animals both when given as a single compound or as a technical mixture (25-29). Some of chloronaphthalene congeners indicate relatively high dioxin-like toxicity (EROD, AHH), and a few have their 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalence factors (TCDD TEFs) (27, 29). The 7-ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH)-inducing potencies of the Halowax 1014 mixture in a test with the chick (Gallus domesticus) embryos were
S0013-936X(96)00254-4 CCC: $12.00
1996 American Chemical Society
FIGURE 1. Sampling locations of plankton (b), harbour porpoise (O), and Herring (*) in the southern part of the Baltic Sea.
estimated for 200 µg kg-1 egg and for an equivalent mixture of 1,2,3,4,6,7- and 1,2,3,5,6,7-H6CN (PCN Nos. 66/67) for 60 µg kg-1 egg. Additionally, chick embryos are less susceptible than those of eider duck (Somateria mollisima) (29). Some unnamed chloronaphthalene congeners, which are planary related to TCDD but other than Nos. 66/67, also seem to be responsible for the relatively high enzyme-inducing potency of Halowax 1014 (29). Both the technical Halowax 1014 as well as congeners 66/67 and 73 cause hepatic lesions in exposed chick and eider duck embryos. An equivalent mixture of congeners 66 and 67 is much more lethal to chick and eider duck embryos than the technical mixture of Halowax 1014. Congener 73 is much less potent in its AHH- and ERODinducing potency and is much less embryo lethal than Nos. 66/67 or Halowax 1014 (29). When compared to polychlorinated biphenyls (PCBs), our detailed knowledge about the sources, distribution, fate, and environmental effects of PCNs is generally lacking. This was mainly due to not-specific and not-sensitive enough analytical methods that were used. Within this study are presented congener-specific data on spatial distribution of many PCN congeners in subsurface mixed plankton samples collected from the southern part of the Baltic Sea and also on the occurence and behavior of these xenobiotics in a pelagic food chain including plankton; herring (Clupea harengus), feeding exclusively on plankton; and harbour porpoise (Phocoena phocoena), feeding mainly on herring.
Materials and Methods Collection of Samples. Four samples of mixed phyto- and zooplankton, three whole individuals of herring (Clupea harengus), and four blubber samples from harbour porpoise (Phocoena phocoena) were collected in the southern part of the Baltic Sea in 1991-1993. The sampling sites of the material examined are shown in Figure 1, while details of the composition of mixed plankton samples collected during a research cruise of the R/V Oceania in September 1992 are summarized in Table 1. Herring (body length 21-22 cm) was collected in the Gulf of Gdan ˜ sk in August 1992. Harbour porpoises were collected near Wladyslawowo on December 22, 1991 (female 1; body weight 38.8 kg, body length 131 cm) and on October 1, 1993 (female 2; body weight 50 kg, body length 128 cm), near Miedzyzdroje on January 7, 1992 (male 2; body weight 44.8 kg, body length 129 cm), and near Leba on January 29, 1992 (male 1; body weight 38.4 kg, body length 131 cm). Chemical Analyses. The analytical method used for the determination of chloronaphthalenes is part of a multiresidue procedure performed in parallel analysis of many organochlorines and polynuclear aromatic hydrocarbons
(PAHs) (30-32). After homogenization of the sample (77378 g) with anhydrous sodium sulfate, which was baked at 550 °C for 2 days, a powdered mixture was packed into a wide bore open glass column (1-1.5 m × 4 cm i.d.), spiked with an internal standard ([13C12]3,3′,4,4′,5-pentachlorobiphenyl; PCB 126), extracted with a 500-mL mixture of acetone and n-hexane (2.5:1) and 500 mL of n-hexane and diethyl ether (9:1) to obtain a fat extract. Bulk lipid removal was performed by means of polyethylene film dialysis method (30, 32). After dissolving the extracted lipids in cyclopentane, dialysis through the polymeric mebrane was accomplished by changing the dialysate after 24, 48, and 72 h. The three dialysate fractions, containing normally between 1 and 10% of the original lipids, depending on sample size and matrix type, were combined and concentrated to 3 mL using a rotary evaporator. The extract was split into two parts, of which 90% was used for analysis of PCNs and some other planar compounds not described here, while 10% was used for the analysis of organochlorine pesticides and bulk of PCBs. The remaining fat was removed on a combined silica column (20 cm × 38 mm i.d.) packed as follows from the bottom: glass wool, potasium silicate (10 mL), a layer of neutral silica gel, 40% sulfuric acid silica gel (20 mL), and a layer of anhydrous sodium sulfate on the top. The gravimetric elution of planar organochlorines was done with 200 mL of n-hexane, and 40 µL of tetradecane was added as a keeper before evaporation of the solvent. The extract was then fractionated on HPLC using an activated carbon column (Amoco PX-2; 2-10 µm, dispersed on LiChrospher RP-18; 15-25 µm). Between the carbon column and the precolumn, a filter valve (Valco Instruments Co. Inc., TX) was mounted, enabling backflush of the column. The elution from the HPLC carbon column was performed with 1% methylene chloride in n-hexane for 7.5 min, solvent 1, and then gradient elution up to 10% toluene for 32.5 min, solvent 2 (Burdick and Jackson, Muskegon, MI), degassed with argon. Fraction one, containing organochlorine pesticides and 2-4 ortho PCBs, is collected during the first 15 min, and fraction two, containing mono-ortho PCBs, is collected between 15 and 40 min. The total volume of the solvents used was 160 mL, and the flow rate was 4 mL/min. PCNs together with PCDDs, PCDFs, and non-ortho planar PCBs were reverse eluted in fraction three with 80 mL of toluene. The eluate was concentrated and spiked with [13C12]-2,2′,4,5,5′-pentachlorobiphenyl (PCB No. 101) as a recovery standard and evaporated to a final volume of 30 µL with tetradecane added as a keeper. A gas chromatograph (Hewlett Packard 5890 GC) coupled to a mass spectrometer (VG Analytical 11-250 J, Altrincham, United Kingdom) was used for the determination of PCN congeners. The mass resolution of the mass spectrometer (MS) was 8000 MU. Injections were made using splitless mode, and the oven was temperature programmed as follows: initial temperature 180 °C, initial time 2 min; rate 1, 20 °C/min to 200 °C, rate 2, 4 °C/min to final temperature 300 °C and final time 15 min. A Rtx-5 fused silica capillary column (60 m × 0.32 mm i.d.), coated with crossbond 5% diphenyl-95% dimethyl polysiloxane with a film thickness of 0.25 µm was employed for the analysis. The ion source was kept at 250 °C and operated under electron ionization (EI) conditions at 70eV, and the MS was tuned in the selected ion monitorng (SIM) mode. For the confirmation/ quantification of PCNs, the two most abundant ions in the chlorine cluster of the molecular ion were monitored at
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TABLE 1
Description of Plankton Samples sample weight (g)
sampling site and date
composition
Gdansk Deep 54°49′ N, 19°20′ E Sep 26, 1992 Gotland Basin 55°30′ N, 18°00′ E Sept 25, 1992 Bornholm Basin 55°10′ N, 16°20′ E Sept 23, 1992 Pomeranian Bay 55°20′ N, 14°14′ E Sept 22, 1992
Chaetoceros spp., Coscinodiscus spp., Nodularia spp., Anabaena spp., Prosocentrum spp., Aphanisomenon spp., Copapodi spp., Nauplii spp., Bosnina spp., Keratella spp., Cladocera spp. Chaetoceros spp., Coscinodiscus spp., Nodularia spp., Anabaena spp., Ainophysis norwegie, A. rotundote, Prosocentrum spp., Aphanisomenon spp., Copapoditi spp., Nauplii spp., Bosnina spp., Bivalvia juvenalis (larves), Tintinoidea spp. (larves), Protozoa spp. (larves). Coscinodiscus spp, Nodularia spumigena, Copapoditi spp., Keratella spp., Cladocera spp.
146.2
Coscinodiscus spp., Protocentrum minimum, Copapoditi spp., Keratella spp., Cladocera spp.
77.0
m/z 263.9 and 265.9 for tetra-CNs, m/z 297.9 and 299.9 for penta-CNs, m/z 331.8 and 333.8 for hexa-CNs, and m/z 365.8 and 367.8 for hepta-CNs. Isotopically labeled PCBs 126 (internal standard) and 101 (recovery standard) were used for compensation of possible losses during the enrichment procedure. A procedural blank was performed with every set of the real samples analyzed. The technical mixture Halowax 1014 was used to determine elution order and pattern of PCNs in the sample chromatograms. Appropriate chromatographic data published for Halowax 1014 by Wiedmann and Ballschmiter (8), Nakano et al. (9), Takasuga et al. (10), and Imagawa and Yamashita (12) were used to identify the ellution pattern of tetra- to hexa-CNs on the Rtx-5 capillary column chromatograms in this study. Chloronaphthalene Nos. 66/67, 71, and 73 (synthesized by Dr. Eva Jakobsson, Stockholm University) were native standards used together with the above-mentioned PCBs 101 and 126 for GC/MS quantification based on the peak area, and the results were corrected for recoveries. The hexa- and hepta-CNs were quantified on the basis of the molar response (MR) factors of congeners 66/67, 71, and 73, respectively. Since the standards of individual native mono- through penta-CNs or their 13C12-labeled analogues were not available during the course of analysis, the MR (SIM) factors of hexa-CNs were used to quantify the tetraand penta-CNs without correction for the differences in the ionization cross-section (Q), which is 33.7, 36.9, and 40.1 × 10-16 cm2 for the tetra-, penta-, and hexa-CNs, respectively (8).
Results and Discussion Concentrations. Forty-four of 48 theoretically possible tetra- throught hepta-CN congeners were quantified in plankton, herring, and harbour porpoise (Table 2). Nevertheless, some of tetra-, penta-, and hexa-CNs were not resolved one from another on the Rtx-5 capillary column and co-elluted in pairs (four tetra-, two penta-, and six hexa-CNs) or triplicate (six tetra-CNs) on the chromatograms. Two tetra-CNs, i.e., 1,2,3,4-T4CN (No. 27) (which has all carbons on one ring substituted and one on the second ring unsubstituted with chlorine) and 1,2,3,7-T4CN (No. 30) (which has three vicinal (R, R, and β) positions unsubstituted with chlorine), were absent on the chromatograms. 1,2,6,7-T4CN (No. 44), which is eluting shortly before 1,4,6,7-P4CN (No. 47) on the DB-5 (an analogue to the Rtx-5) capillary column (10), seems to be present in very low concentration but was not quantified in the samples examined. The potential presence of 1,2,6,7-T4CN
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219.2 108.8
in biological samples needs to be further confirmed. Both 1,2,3,4- and 1,2,3,7-T4CN are trace constituents in Halowax 1014, and their contribution to the total tetra-CNs in that technical mixture is only 0.3 and 0.2%, respectively (11), while 1,2,6,7-T4CN is absent in Halowax 1014 (12). Since 1,2,6,7-T4CN was found as a main tetra-CN constituent in fly ash (12), the environmental sources of that congener and its presence in biological samples could be related to thermal reactions including waste incineration processes. The only hexa-CN not found in plankton, herring, and harbour porpoise was 1,2,3,6,7,8-H6CN (No. 70). That hexaCN congener, which has two vicinal carbon atoms at R,Rpositions (4,5-positions) unsubstituted with chlorine, is absent in Halowax 1014 and is only a trace constituent among of hexa-CNs in fly ash from the municipal incinerator (12). When expressed on a lipid weight basis, herring showed the largest concentration (29 000 pg g-1) of the total PCNs, while a spatially different gradient from 7 500 to 20 000 pg g-1 was observed for subsurface plankton. For harbour porpoise, the values were lowest and ranged between 1700 and 2800 pg g-1 (Table 2). There are no data available in scientific literature to compare the concentrations found with samples of similar nature and originating from the other areas of the Baltic or other seas. In a report by Ja¨rnberg et al. (18), quantitaive data for several unidentified PCN congeners were given for herring, and due to cleanup problems, no PCNs were reported for harbour porpoise. Profile. The profile of tetra-, penta-, hexa-, and heptaCNs found in examined subsurface plankton is very similar in spite of geographically distant sampling sites. Relatively more volatile and also more hydrophilic tetra-CNs (17) are a highly dominating PCN congener group in plankton and occupy from 79 to 82% in the total PCNs quantified. Tetrachloronaphthalenes, with 56-65%, were also the most contributing group to the total PCNs in harbour porpoise and in herring occupied 45%. Pentachloronaphthalenes contributed 50% to the total PCNs in herring, while only contributing from 17 to 19% in plankton and from 11 to 20% in harbour porpoise. Hexachloronaphthalenes showed the lowest abundance in plankton samples, while they were progressively higher in herring and harbour porpoise with 0.85-1.3%, 5.2%, and 22-30%, respectively. Heptachloronaphthalenes occupied from 0.14 to 0.32% in plankton, 0.24% in herring, and 1.7-2.5% in harbour porpoise. The profile of these four PCN congener groups found in the biological samples examined is largely different from that observed in a technical mixture of Halowax 1014 (with 18,
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a
From ref 8.
73 74
66/67 64/68 69 71/72 63 65
b
24
ND, not detected.
7500
total hepta-CNs
total PCNs
12 12
97
total hexa-CNs
1,2,3,4,5,6,7-H7CN 1,2,3,4,5,6,8-H7CN
41 13 19 16 5.7 2.3
1400
1,2,3,4,6,7-/1,2,3,5,6,7-H6CN 1,2,3,4,5,7-/1,2,3,5,6,8-H6CN 1,2,3,5,7,8-H6CN 1,2,4,5,6,8-/1,2,4,5,7,8-H6CN 1,2,3,4,5,6-H6CN 1,2,3,4,5,8-H6CN
total penta-CNs
290 37 340 82 30 14 120 150 150 160 14 5.6
total tetra-CNs
1,2,3,5,7-/1,2,4,6,7-P5CN 1,2,4,5,7-P5CN 1,2,4,6,8-P5CN 1,2,3,4,6-P5CN 1,2,3,5,6-P5CN 1,2,3,6,7-P5CN 1,2,4,5,6-P5CN 1,2,4,7,8-P5CN 1,2,3,5,8-/1,2,3,6,8-P5CN 1,2,4,5,8-P5CN 1,2,3,4,5-P5CN 1,2,3,7,8-P5CN
6000
1,3,5,7-T4CN 1,2,4,6-/1,2,4,7-/1,2,5,7-T4CN 1,4,6,7-T4CN 1,2,5,6-/1,3,6,8-T4CN 1,2,3,5-/1,3,5,8-T4CN 1,2,3,4-/1,2,3,7-/1,2,6,7-T4CN 1,2,4,5-/2,3,6,7-T4CN 1,2,4,8-T4CN 1,2,5,8-/1,2,6,8-T4CN 1,4,5,8-T4CN 1,2,7,8-T4CN
42 33/34/37 47 36/45 28/43 27/30/39 32/48 35 38/40 46 41
52/60 58 61 50 51 54 57 62 53/55 59 49 56
460 1500 690 79 780 180 74 420 1200 530 79
structure
PCN No.a
plankton Gdan˜sk Deep 1.85
17000
32
16 16
140
72 16 19 19 9.3 7.0
2900
470 49 540 240 84 40 340 280 310 460 35 17
14000
310 3000 1400 140 1800 560 180 1000 3600 1400 240
plankton Gotland Basin 1.10
17000
47
31 16
Heptachloronaphthalenes
190
83 23 31 29 7.8 13
Hexachloronaphthalenes
3300
560 34 590 260 73 23 380 320 400 560 73 29
Pentachloronaphthalenes
14000
310 2800 1400 160 1700 550 200 1100 3700 1500 230
20000
29
19 10
180
56 22 28 42 22 11
3900
710 45 670 370 84 34 450 390 470 610 73 34
16000
340 3600 1900 140 1900 730 280 1500 3900 1600 250
plankton Pomeranian Bay 1.08
Tetrachloronaphthalenes
plankton Bornholm Basin 0.84
29000
70
37 33
1500
450 210 390 340 64 54
15000
4500 490 4400 260 64 150 1000 1300 1000 1300 100 42
13000
3500 2600 1900 96 1300 240 210 1800 840 610 32
herring Gulf of Gdan˜sk 9.0
1700
36
15 21
380
370 4.3 3.9 1.6 NDb ND
330
110 8.6 63 26 51 9.7 14 19 17 12 0.78
